The Third Child
by Amaterasu Verdana
Summary: Sans is sitting at his sentry post making a hotdog, and finds a crying woman. An incident in the bathroom leads to a final battle. Through these events Sans realizes that the Third Anomaly has appeared. But will he end it's life and put a stop to the timeline changing? Or will he fight alongside them to defeat a greater threat?
1. Introductionism

_Writer's Note: Hi. I'm Amaterasu of Hyrule, as you can see. This is my first fanfic, so please don't judge me too harshly. Also, I just wanted to let you know that this fanfic will not have, and will never, have swear words or adult themes, but will have violence, pain, and LOTS of confusing plot points. Just wanted to give you a heads-up._

One day, Sans was sitting at his sentry post in the forest of Snowdin. He was really tired and was just about to fall back asleep when he heard sobbing somewhere behind him. He gets up and tries to find the source of the sound. He walks into a clearing and finds a woman sitting on the ground in a ball, backed against a tree. She almost looks human, except that she has dog ears, and is wearing a kimono. "Heya. What's wrong?" Sans asks the woman. She doesn't reply, but instead retreats further into herself. "Hey, don't be sad. Whatever happened, it's over. Everything is okay now." Sans tried to comfort the woman. She muttered something inaudible. "Hey. You gonna tell me what's wrong, or are you just gonna leave me hangin'?"

"Help me. Please, help me!" She cries, louder in the second sentence.

"Um, hey. What exactly do you need me to help you with?"

"My friend was corrupted, and I can't help him because I'll be corrupted too." She tells Sans.

"Okay, then let's take you to my house. You look cold and starving, and you might want to get some _meat on those bones_ , yeah? I'm guessing you might wanna discuss this in a better place, too?"

"Seriously?" That's how you're going to make a first impression? Wow. I can't believe what's happened to standards here."

"What? I was trying to get you to feel better. But, I guess, to each their own.

About an hour later, they were in Sans' room. They had discussed Sans' life. "So, that's the gist of it, huh? The woman stated, blank-minded and staring.

"Yep. So, how about you? First of all, I haven't asked you your name this whole time. That was a screw-up on me, wasn't it?" Sans stated, with a chuckle. The woman eventually replied, "My name is Amaterasu. But you can just call me Ammy."

"Okay, Ammy. What's up with you? Earlier, all you told me was that-"He stated questioningly, until he was interrupted by the door opening.

Papyrus walks in and says, "Sans! Have you sorted out the problem yet?" Papyrus says, "I hope so, because I have finished preparing dinner. Please, come eat."

"This spaghetti is really good, Papyrus. You've really improved at cooking." Sans says.

"What about you, Ammy?" What do you think of it?"

No response.

"Ammy?"...No response. "AMMY!?" Still, no next second, she's in the bathroom, shutting the door.

"Did she just… teleport?" Papyrus asks.

"Yes. Yes she just did." Sans answers, wide-eyed. They hear screaming coming from the bathroom and rush toward the door.


	2. Puns and a Lab

_Writer's Note: The portal mark left in this chapter, and all other chapters, is the same one found in_ Pokemon:Mystery Dungeon: Gates to Infinity.

Papyrus tried to open the door, but it was forced shut by some pressure coming from the inside. Sans was about to teleport inside when a great shockwave hit them. They couldn't see for a moment, but then the bathroom door, and the frame, were lodged in the wall across the room. Sans blinked the light out of his eyesockets only to see Papyrus staring in disbelief at the remnants of what was their bathroom. Sans followed his brother's gaze, then gaped at what he saw. A charred mark left in the floor, with a filament of smoke trailing up from the mark. The mark itself was similar to a black hole. "What the…" managed Papyrus, still gaping. "S-Sans, w-what is that?" managed Papyrus, still in shock.

"I don't know, Papyrus. Guess you could say it's a mist-ery."

"OH MY GOD SANS!" shouts Papyrus.

"Anyways, let's see what this is…" Sans says, curiously.

Some time later, Sans and Papyrus call Alphys and now she and Undyne are there, and everyone is looking at the mark. Sans leaves. "W-where did he go, Papyrus?" Alphys asks.

"He probably just went to his secret back room." Papyrus answers.

"Where is it?" asks Undyne.

"Around the back." Papyrus answers again.

They all head out and to the door. Alphys tries to open it, but the door is locked. Sans calls from inside, "Who's there?"

"I-It's just us, Sans. C-Can we come in?" Alphys stutters.

"Sure, but only Alphys." Sans replies. A click is heard from the door. "Come on in, Alphys." Alphys hurries in and shuts the door behind her.

"Let's go before those losers want us to listen to their babble. It's probably not important anyway. " Undyne says. They all walk back to the house.

"So, the mark is similar to a black hole, right?" Alphys says.

"Yeah. Hang on, let me get out some of Gaster's notes." Sans replies.

"Y-You have Gaster's notes!?" Alphys stutters, shocked.

"Well yeah, I was his colleague. We worked on... things together." Sans says, then shakes his head as if ridding himself of the thought.

"Well, I won't ask into it, it seems to be a sore subject, but, did you work on anything like this?" Alphys says, sounding curious.

"Yeah" Sans says, "although not exactly. It could be void magic, or maybe a form of interdimensional travel."

"Looks to be the latter." Alphys responds.

 _Author's Note: I've been busy at school MAP testing, so it took me longer than I wanted to update. Also, for those of you who don't know, this fanfic was rated "Teen" for violence ONLY. There will not, and never will, be major swearing or adult themes. I may use the word crap occasionally, but this is a mainly kid-friendly story. Remember, the rating system is your friend. If you don't want to read about people dying, or Undertale characters duetting opera with Inuyasha characters in falsetto, DON'T READ THIS! (I know it's a little bit late for that, just needed to get the feels out, ya know?)_


	3. Sarcasm and Explosions

"Okay then. Let's begin. We know that it was caused by magic," Sans says, "So, that means we can narrow our choices down to either void magic or interdimensional teleportation."

"W-Well, judging by the mark left, it could use portal gateways." Alphys added.

"Good, good. Next, why would she leave like this?" Sans replied.

"M-Maybe she was suffering. You know, like that AU, BOTWOT, except different?"

"Hmm. That's good info, but it may be just a theory. Hopefully we can solve this."

"I-I think that m-maybe we could just u-um, you know, take some s-samples?"

"Good idea."

Later, they were back in the lab. Sans was investigating the samples they took."The marks were made with a gateway. Hmm… Interesting. The gateway was composed of LOVE and Photoignesium."

"LOVE? Okay, seems somewhat normal but… what exactly **is** photoignesium?"

"Photoignesium is an element I recently discovered. It's basically void fire."

"W-Wait. You said that you u-um.. D-discovered it, right?"

"Yeah."

"Then, w-wouldn't that mean m-maybe **she created** it?"

"Yeah, you're right. But, why would that gateway be composed of it?"

Meanwhile…

"Whew. Glad I got out of that one. The timelines.. Just.. woah-kay, little bit of blowback.."

"Ammy."

"Yeah, Gaster?"

"Why did you use the void gateway?"

"I wanted to lead them to you."

"Oh, ok."

"Aaaaaaa-nyways, I wanted to show you the new thing I found with Photoignesium."

"You mean you found a way to combine Photoignesium with other elements?"

"Yes. I've combined it with light. **Only** light. Wanna see?"

"Sure."

Mean-meanwhile…(Is that even a word?)

"This is puzzling. Sans and Alphys are still working, and it is almost time for dinner!" Papyrus said, worriedly.

"Well, let's go check on them." Undyne replied.

An explosion. Screaming.

 _Author's note: Yay cliffhangers! Just kidding. I know this chapter is about as long as the first two combined, but I really couldn't find a good stopping point. Special thanks to ElizaViolet for supporting me personally with ideas and stuff, and to Red Diz for commenting, reviewing, and eagerness. I thank you both from the bottom of my heart._


	4. Re: Introductionism

"Undyne, what was that?" Papyrus asked, looking confused.

"I don't know, Papyrus. Has that happened before?"

"Yes, actually, it has, when, 'you know' happened."

"Well, we should check on them."

"Yes, definitely."

Moments later, Papyrus and Undyne were standing around the remains of Sans' "secret back room". Undyne noted that the room was charred, and the same mark from earlier was charred in the floor. Standing on the mark was a slender lady. She had fiery red hair tied back in a ponytail, red pointed dog ears on her head, shining yellow eyes, and facial markings. She wore a simple white kimono with golden trim.

"Who are you?" Undyne called out to the figure.

Movement in the rubble. Sans's hand shot out of the rubble, the sleeve of his hoodie in tatters. He pulled himself up, and pushed another block near him to the side. Alphys was laying there, bruised, with multiple pieces of debris lodged in gashes along her scales.

"Oh my god! Is Alphys okay?" Undyne gasped, horrified.

"She'll be alright. I told her to get down as soon as I sensed the energy building. Pap, you should take her into the house." Sans said, sounding exhausted.

"Okay, brother." Papyrus replied, walking over to the pile of rubble where Alphys lay, unconscious, bent over, scooped her up, and with her in his arms, walked back around the house and entered the front door.

"Anyways, who are you?" said Undyne, quickly changing the subject.

"My name is Ammy. I had to come back. I saw what happened. And Sans, sorry for blowing up two rooms in your house." Ammy said, sounding guilty.

"S'fine. After all, I can just rebuild it, can't I?"

"Publicity, Sans. Publicity. How can you forget other people are going to start asking questions?"

"Oh."

"Hey, what's your name?" Ammy asked Undyne.

"My name is Undyne, and I'm the Captain of the Royal Guard."

"That's nice to know."

"Hey. Ammy. I want to fight you."

"W-What? Why?" Ammy asks, shocked.

"I wanna see how strong you are."

"Oh. Ok."

 _Writer's Note: More cliffhangers. I just want to let you know that maybe I could, y'know, start to recommend music for you, the reader, to listen to. I'd like to recommend Judgement by TryHardNinja. It's an Undertale fan song from Sans's perspective, and it's a great song. Just go onto YouTube and search, "judgement tryhardninja". You can capitalize if you want._


	5. Action Sequences

Undyne summoned a spear and lowered herself into a battle stance. Ammy drew her sword and lowered herself. Ammy rushed towards Undyne, but Undyne blocked Ammy's sword with a clash. They struggled, and Ammy reached out and slashed Undyne with her claws. Undyne staggered back, and Ammy sheathed her sword.

"W-What..? H-How..could I...be.. Defeated..?" Undyne said, gasping.

Ammy looked bored. She looked Sans in the eye, and said, "Sans. Fight me."

"You think I'll fight you? After what you did to Undyne? Well, you're...correct. I've gotta see what you're really made of. I know you're holding back."

Meanwhile…

"Sigh. When will a human fall? I'm bored out of my mind right now." said Chara.

Now back to the main story…

Ammy sunk once more into a battle stance and drew her sword. Sans walked forward to meet her gaze. She rushed at him, but Sans sidestepped and sent bones flying at her like projectiles. Ammy held her sword and blocked them. She poised, sword held back, swung, and yelled, "Getsuga Tenshou!". A light-blue and white beam of energy in the shape of the blade shot forth. Sans teleported out of the way at the last second and reappeared behind her. He summoned a gaster blaster and prepared to fire square at her back, but she spun and elbowed him. He recoiled and Ammy rushed in, only to teleport away when he fired the gaster blaster at her. Ammy reappeared some distance away and sheathed her sword, returning her blade to a smaller form, and unsheathed another sword from a sheath slung over her shoulder. This sword was more traditionally shaped, with a twisting, beautifully carved pommel and grip, and set in the bottom of the grip was a spherical magenta gem. The blade was then surrounded by a swirling, semi-transparent vortex of magenta magic. She poised once more, ready to strike, but then Flowey suddenly popped up and shot a tendril at her. She teleported out of the way.

"Howdy! I sensed that there was something going on. That must have been some powerful magic you were using if I sensed it all the way from the Ruins! So, what was that?" Flowey stated, his thorny tendril snaking back underground.

"Gateway." Ammy stated, narrowing her eyes at the mysterious flower.

"Gateway? To what?" Flowey replied, still sounding cheerful, but narrowed his eyes.

"To the void. Speaking of the void, I brought Gaster." Ammy said, turning to face Gaster, and pointed.

"Hi. I'm back from the void. Sans, Papyrus, my sons. How have you been doing?" Gaster stated happily.

"I'm glad you're back, dad, but.. I'm not really doing well." Sans stated, his mood darkening.

"Dad.. I'm so happy that you're back! I can't wait to show you what we've done!" Papyrus stated cheerfully.

Sans, moaned sickly, then collapsed. Everyone gasped. Papyrus scooped him up and put him in his bed.

 _Writer's Note: More Cliffhangers. I hope you all enjoy, I really hate writing action sequences. Also, please feel free to send an honest review. I appreciate it if you're being polite, but you don't have to lie. If you are being sincere with your comments, please continue to do so._


	6. The Informative Chapter

"Sans and I were having a friendly match. Undyne and Papyrus were inside caring for Alphys. Gaster was salvaging the remains of Sans's lab. So what went wrong? Why did Sans collapse?" Ammy thought to herself, sitting on the roof. Suddenly, the roof panel opened up to her left. Gaster climbed up the ladder and sat on the roof next to Ammy. "Any news?" she said, searching his face for any sign of emotion.

"Good news? Sans is awake. He simply fainted." Gaster replied.

"Good. Anything else?"

"Well, do you want the long explanation, or the paraphrasing?"

"Lay it down for me. I want all the info."

"Okay then. When Sans was unconscious, he was just laying there, right? Well, I was sitting there for a while when his eyes opened. He was using magic in his sleep! A dozen gaster blasters appeared behind him. I backed up. But then Sans started to shake. I knew he was going to change into his true form if I didn't do anything about it, so I talked to him. The gaster blasters disappeared. I stopped when his eyes were glowing green. I left the room, confident that he'd be fine. About 15 minutes later, he woke up. And that's all that happened." Gaster said, contented.

Suddenly, the panel opened again. Sans climbed up, holding a cup of coffee. Ammy saw that the coffee was made of healing magic. "Are you okay, Sans? What happened?"

"I'm fine, I just- woah-kay." Sans said, teetering. Gaster reached out to support him. "Sorry, I just… wait. Ammy, how much do you know?" Sans said, curiously.

"Just lay it down for me. If I ask, you just have to answer. So go ahead." she replied.

"Okay, so I was fighting, and something snapped. I guess I was reaching the threshold. I felt it stack, and….snap. Just like that, I fell." Sans replied, snapping for emphasis.

"So why is there a threshold?" Ammy asked.

"Basically, all skeletons have a 'true form' that they have to use sometimes. Mine is a dragon. And Gaster…" he replied, eyeing Gaster.

"I'm your father." Gaster replied, "of course I passed it down to you. But Papyrus's came from your mother. His is an eagle."

"I knew Papyrus's is."

"Sans, who was your mother?" Ammy asked curiously.

"My mother's name was Hermann. She died." Sans answered, his mood immediately darkening.

"I'm sorry for your loss." Ammy said, her voice wavering.

Sans took a drink from his cup, looked out to the distance, and teleported. Gaster, looking frustrated, teleported after him.

The empty cup fell to the shingles and shattered.


	7. Time for More Characters

The ground shook. Ammy could feel a great force coming. She opened the panel and slid down the ladder. The sheer force of the wind snapped the panel shut. Ammy rushed through the house, telling everyone to get down and find shelter. Papyrus hid under the table. Crouched next to him was Undyne, holding a teal spear. The spear suddenly widened, becoming a shield. Alphys hid in the space under the stairs. Ammy stood there, shaking her head.

"Ammy! Don't just stand there! Get down!" Undyne shouted, "Sans and Gaster can handle themselves!"

"No." Ammy said and teleported away.

The windows started breaking as the full force of the wind battered and shook the house. They could hear crackling noises, as if an earthquake and tornado took hold simultaneously. Glass and other small objects started to fly around the house, and Papyrus summoned bones to cross-shield his side of the table.

Ammy reappeared in the middle of Snowdin Forest. Sans was hiding under a nearby tree. She walked over to him. " _The forces,"_ she thought, _"They're incredible. What could be causing this?"_ "Sans. What is going on?" she said, having to shout over the wind.

"A human's coming." Sans shouted, "so get up this tree, quick."

She arrived at Sans and climbed up until she was on the sturdiest branch and crouched. "Are you sure putting me in a tree is a good idea?" Ammy shouted.

"You'll be fine. You can hold your own."

"Also, where's Gaster? I don't see him."

"Hi. I'm below you."Gaster said, "could you help me up?"

"I got'cha." Ammy said, grabbing his hand and pulling him up.

Suddenly, a purple door to their left opened. Sans crouched, ready to chase whoever came out. Out of the door came…

 _Writer's Note: This chapter is very short. Also, prepare to be disappointed._

… a small human child wearing a blue, purple striped sweater. They walked out of the door casually, a tall goat lady standing in the door smiling. The human turned and waved before setting off forward once again. Sans, slinking out of the bushes, stealthily as a cat, stalked the human. He pulled something out of his pocket; a whoopee cushion. When the human reached the bridge. He stopped. "Don't you know how to greet a new pal?" Sans said, threateningly, "Human. Turn around and shake my hand."

The human slowly turned and shook his hand. **blort** "Ah. The old whoopee cushion in the hand trick." Sans chuckled. Sans talked to the human for a little bit before leaving them to go about their business. They were making a snowman. Sans came back to them and said, "Let's go check up on everyone else." They all teleported back to the house, and gaped at what they saw.


	8. Oh No! The Plot!

The house was in ruin. The table was still intact, but shards of glass were everywhere. The picture of a bone they had on the upstairs wall was now just shards of glass, a piece of paper, and a few sticks. The couch was sticking out of Papyrus's door, and the lock on Sans's door was snapped. Sans hurried up and opened the door to see what happened inside. Gaster followed him up and gaped. Sans's room was still intact! "Well, that's…. surprising," Sans said, not actually looking very surprised.

Ammy went into the kitchen and said, "Guys, you might want to come see this!" Everyone walked in beside her, and saw…

 _Writer's Note: This time, I won't disappoint you. Also, this is where the plot starts off._

….Flowey, huddled up in the cabinet under the sink. Ammy bent over and plucked the flower out of the ground. Flowey snarled. Ammy bared her fangs and said, " **Well well well. Look what we have here. A tiny, soulless flower."** She stared straight at him. A tiny spark ignited deep within him, where his soul would be. **"Oh, look! The soulless husk has a soul! All the easier for me to-"** she paused, **"KILL HIM."** Ammy's face spread into a maniacal grin. Flowey shrieked. She pulled her hand back. Flowey pulled his head backwards. Ammy tensed, ready to strike, but Sans put his hand in the way and pimp-smacked Ammy. She roared and crouched. He summoned gaster blasters. Ammy pulled out the sword with the magenta gem and swung. A tornado of magenta magic swirled towards him. He teleported out of the way, but Ammy was already there. Her eyes glowed crimson, the pupils narrowing and becoming bright sky-blue. The sheer force of her glare intimidated Sans, and he took a step back. "Come any closer, " she growled, her voice low, "and you'll have more than a threshold to worry about."

"Please, Ammy," Sans pleaded, his voice wavering, "I know you're not like this."

Her eyes widened and became their usual golden yellow. She stood up, sheathing her sword. Flowey opened his mouth to speak, but her glare silenced him. "What happened, Ammy? Why did you do that?" Sans said.

"I..I..I don't want to talk about it." Ammy said in a quiet voice.

"What is going on? I don't understand.." said Papyrus, drawing their attention to everyone else in the room.

"I..had a mishap. Don't worry about it, it won't happen again." she said, her voice still quiet.

"Are you sure, Ammy? That was.. really intimidating, actually. What happened?" said Undyne.

Ammy teleported away, and this time, even Gaster didn't know where she went.


	9. Foreshadowing

The human's feet crunched through the snow. " _It's so cold.."_ they thought, _"I wish I brought a jacket. Will anyone else come through here soon? I don't know where to go._ " They continued onwards, seeing Sans waiting for them.

"Quick. Hide behind that conveniently-shaped lamp." he said, and they did. But instead of Papyrus, Ammy staggered out of the trees. Seeing another person in such a bad state, the human reached over and helped support her.

"Thanks.." Ammy said, clearly sounding out of it.

Sans went over and helped her too. "What happened to you, Ammy? Why did you just leave without telling us where you were going and then just reappear, injured?"

"I-I don't think you'd want to know.." Ammy coughed.

"Tell us, Ammy. I'm worried about you, you know."

She wavered, and said weakly, "I-I was at the CORE."

"Why?"

"Science, Sans. Any other reasons you can think of?"

"..."

"Exactly," Ammy said, then coughed and kneeled. Her kimono was stained red, and a single drop of blood escaped from beneath her teeth. Sans bent over and took her in his arms. He said, "Kid. Hold on tight to my arm." The human grabbed on as if it were life or death. Sans teleported. They reappeared in Sans and Papyrus's house, startling everyone there. Undyne did a double take. The human reopened their eyes and was greeted by a cleaner-looking house than it's state when Ammy teleported out. Undyne then stood tall, a shimmering teal light appearing in her palm and forming into a spear. The human hugged Sans' arm tighter as Undyne approached. "Leave the human alone," Sans said, "the kid hasn't done anything wrong."

"But Sans, humans are dangerous! They could kill us at any moment if we let our guard down!" Undyne said defiantly.

"I said. The kid. Hasn't. Done anything wrong." Sans replied threateningly.

Flowey said, "Um..hello? Anyone going to look at me? No? Okay.."

Undyne relaxed. Papyrus, kind as always, asked, "Human! Would you like some spaghetti? Are you hungry?" The human nodded. Papyrus went into the kitchen and started making spaghetti.

"U-Um, human..what's your name?" Alphys asked timidly. The human signed, "My name is Frisk." Alphys shook her head. "I don't know sign language." Sans said, "They said their name was Frisk."

"Sans, I didn't know that you knew sign language! When did you learn?" Alphys asked, surprised.

"Don't worry about it. It happened a long time ago."

The door opened. Gaster walked in. "Hi dad." Sans said.

Frisk signed, "Hi. What are your names?"

Gaster replied, "Hello, little one. I am Dr. Gaster. You said you wanted to know what our names were?" Frisk nodded.

"My name's Sans."

"And I-I'm Alphys."

Frisk signed, "Where's your bathroom?"

Sans laid Ammy down on the couch and put a blanket over her. Grabbing a paper towel, he wiped the blood off her mouth. Sans then stood up and went into the kitchen. Frisk asked, "Hello? Can I please use your bathroom?"

Gaster replied, "I would just go out back in the woods." Frisk wrinkled their face and signed, "Why don't you have a bathroom? Is it because skeletons live here?"

Alphys replied, "A-Actually, i-it's because, um… you see, that w-woman over there kinda...b-blew it up..?

Frisk signed, "Oh. Thanks. I'll just go out back."

Flowey disappeared underground then reappeared in the living room. His tendrils snaked through the floor and began to reassemble the room. "T-Thanks, Flowey," Alphys said.

"No problem. But, I'm only doing it because when she wakes up, that woman **will** kill me if I don't."

Gaster walked into the kitchen and helped Sans and Papyrus. Alphys could hear a strange, but gentle voice. It was coming from the couch. She looked over at Undyne, who was still standing there. "Undyne, did you hear that?"

"What, that strange noise? That's coming from Ammy's direction?"

"Y-Yeah, that one."

"Weird. I don't recognize any of the sounds, though."

The gentle voice suddenly became distorted. An invisible force caused the air in the room to still and thicken. The voice was raspy, saying things in a language foreign to them. Frisk, however, seemed to recognize the words. Gaster walked into the living room, speaking in the same language. Him and the sound seemed to communicate, until… the sound stopped completely. The air pressure returned to normal and Gaster walked back into the kitchen. Frisk went out the door. Alphys figured that Frisk was just using the bathroom.

It was cold. Ammy recognized this place, and yet she could never get used to the feeling. The mists surrounded her, and she could only see a blur of red and silver, until the fog cleared. She could clearly see her brother now. "Hi, Inuyasha." She said, her smile widening.

"Hey. Why did you contact me like this? You could've just visited."

"I'm stuck in a timeline. Worse, I'm really injured. I won't be using spacetime travel anytime soon."

"Oh. Sorry to hear that. Just please visit soon. Life is getting really repetitive without you here."

"Sorry about that. I'll come visit soon. Just please wait until I've recovered enough, and I'll come back."

"Okay. Well, see you then! Bye!"

"Bye."

Ammy jolted awake. Alphys and Undyne were startled, and even Flowey stopped. Frisk stood there, staring. Ammy suddenly remembered collapsing in the kid's arms, and felt sorry for them. She immediately noticed that Flowey had cleaned up the majority of the house. "How long have I been out?" she asked, to noone in particular.

"About..oh, um… 3 hours."

"Huh. What did I expect?"

Frisk entered back in. Papyrus came out of the kitchen holding plates of spaghetti, only to drop them upon seeing Ammy awake. Sans, standing behind him, dove and caught the plates just before they hit the ground. Gaster was on the other side, holding more plates. He didn't look surprised to see Ammy awake. Ammy glanced at him. He signed, and Ammy signed back, pointing to Frisk. Frisk signed. Sans said, handing the plates to Papyrus and pushing himself off the floor, "Hey, can you three actually talk out loud? Or are you going to keep half the people in the room in the dark?"

"It's personal, Sans." Ammy replied, sounding annoyed. She pulled something out of her sheath. Sans instantly recoiled. It was the sword with the magenta gem. She pulled something else out of her inventory. Sans recognized it as a whetstone. But what Ammy did with it was **not** what you were supposed to do with a whetstone. She threw the rock right at Sans. He caught it just before it hit his face. She then drew the stone against her sword, then repeated what she did before, until the metal of the sword's blade shone with a faint blue tinge. "It's done." She said.

"Ammy, what was that for?"

"I put your magic on this blade, Sans."

"Why?"

"Come over here and touch it.


	10. Required Filler Content and Plot Stuff

When Sans touched the blade, the blade glowed with a cobalt hue. Sans took his hand off, and the glow dimmed. "Huh," he said, "that's….weird."

Flowey's tendrils slinked back underground. Undyne looked around. The house looked almost as good as before, save a few holes.

Ammy said, "Alphys, could we use your lab?"

"Sure, Ammy, but why?"

"Oh.. just, you know, science and stuff."

Sans intervened. "Can I join in, too?"

"How about we all go?" Gaster said. Everyone nodded.

Later….

"So let's begin." Ammy said, writing some things on the dry-erase board. "What we started with is the Determination, the Magic, and the Force."

"Insert obligatory Star Wars reference here," Sans said.

"That's not what I meant." Ammy wrote a D, an M, and an F.

"So what are we discussing?" Gaster said.

"We're looking at what happened in Chapter 1." she said.

"Wow. Way to break the fourth wall." Sans said.

"Never mind. So let's figure out the order in which everything happened."

"Well, I know that the Force could've come first." Sans said. Ammy wrote a 1 under the F. "Then the magic could've come. You did have a panic attack. So, what was the problem?"

"Well, there was an anomaly. I don't know why it didn't affect you, Sans, but it definitely affected me."

"Maybe it's because it was in a universe that didn't involve another version of us?" Gaster intervened.

"Yeah, let's go with that."

Meanwhile…

Frisk lurched. A reset button shimmered in front of them. They reached for it. Flowey said, "Frisk! No!" Flowey's tendrils whipped out of the ground. But when Frisk's hand hit the button, the button glitched. An error message appeared. Flowey read it. "'Error: Anomaly detected. Fourth-wall break level: 100%.'" "What **is** that? There's only ever been two anomalies, and that's me and Frisk. I wouldn't count, and Frisk's the one trying to reset…*gasp* it must be that Ammy! She's the weirdest monster I've ever seen!"

Now back to science…Ammy had the board at least half filled with equations. There was now a 2 under the M and a 3 under the D. "I should probably stop for now," she said. Gaster and Sans had long since left to do their own project. She could hear the results of that in the next room.

To Sans and Gaster's project…

"Sans! Hit the switch!"

"On it!" Slam! Sans hit said switch. The generator stabilized. The hum of electricity building in the room was neutralized. "Phew."

Ammy walked in, noticing the clipboard Gaster was holding. "What are you guys doing?"

"Oh, we were just exerimenting with a generator that Alphys was using. It's quite different from the ones we used back when... 'you know' happened, but I'm glad the main functions remained the same."

"Huh. Well, I figured out some things. Wanna come see?"

"Sure," Sans said, sounding tired.

Meanwhile, at the house…

"Frisk! Are you alright?" Undyne said, looking panicked.

"Y-Yeah...I really don't know what happened."

The sound of the door opening caught their attention. A strange goat woman walked in. "M-My Queen? I-Is it really you?" Undyne stuttered.

"Yes, it is me. However, watching you care to a child, a human one no less, surprises me greatly. Have you perhaps had a change of heart?"

"That I may. My friends helped me to realize that not all humans are savage murderers."

"Oh, that is wonderful! Also, is anyone else here?"

"Yes, your majesty! I, the Great Papyrus, live here with my brother!"

"Wait, Papyrus? As in the same one that monster told me about?"

"Yes! My brother, Sans!"

"Is he also a skeleton?"

"Yes!"

"Sorry to interrupt your little chat, but there's a small problem." Undyne said.

"A small problem? What is it?"

"Does Asgore really want to take the life of this child? Or should we confront him?"

"I agree, Undyne! We should confront him about it and tell him that there is another way!" Papyrus said cheerfully.

Just then, Flowey popped out of the ground. "I can help," he said, "but we'll have to get the others first."

"What others?" Toriel asked.

"Oh, my brother, my father, Alphys, and Ammy! And maybe Mettaton, too!"

"Who is Ammy?" Toriel asked.

"Oh, a monster that Sans found. She's really nice! She's off doing science with Sans and dad!"

"Wait. I only know of one other skeleton. Are you the sons of Dr. Gaster?"

"Yes! Ammy recently brought him back!"

"Okay. Let's go get the others." Undyne said in a finalizing voice.

"We should probably head up." Ammy said.

"Yeah." Sans said.

And thus, they headed up. Walking to the elevator, Gaster hit in a code on the keypad. The elevator doors opened, and closed behind them as the three of them walked in. Sans noticed how Ammy was clutching an envelope. The envelope looked as if it contained something else. Suddenly, the elevator jerked as it arrived at it's intended floor. The doors opened, and once again, the doors closed behind them as the three of them walked out. Gaster noted that Ammy's ears twitched. Seconds later, the door to the rest of the room opened. They walked out. Alphys was on the other side. She opened her mouth to speak, but was interrupted by the main lab door opening. Undyne, Papyrus, the human, and Toriel walked in. She had at this point redonned some of her formalities. "It's an honor to see you again, my lady," Gaster said, taking a bow.

"Oh, none of that silly nonsense! That can be saved for later." she said, then looked around. She stopped, and stared at Ammy. Recognition flared in her eyes for a moment, then she said, "Ah. You must be Ammy. It's a pleasure to finally meet you."

"It's nice to meet you too."

"U-Um, Ammy, what, u-uh.. Happened down there? I heard some noises, and went to investigate, but then I decided not to."

"Well, we'll chloro-fill you in on that later, Alphys," Sans interjected. Undyne and Papyrus did a simultaneous facepalm. "But, I, uh… recognize your voice. Are you that lady from the other side of the door?"

"Yes. Yes I am. My name is Toriel. It's nice to finally see you in person. Papyrus told me your name is Sans, if I'm not mistaken?"

"No, you're right. And it's, uh.. Nice to meet you in person, too." Sans blushed.

 _Writer's Note: I really want to change the plot. And since abadtime's_ Best of Times, Worst of Times: The Sound of Silence _is so freaking popular, I have to pitch in on that. So, I decided to shift the story. Yeeeeah. I made this a Gaster Blaster!Sans AU. Enjoy the rest of the fic! Also, questions can be asked at_ _my tumblr page_ _here. Thanks!_

A gathering and epic speech later…

"Ohhh yesss! Of course I'll join your little questing brigade!"

"Yeah! Let's go!"

"Let's show Asgore!"

"YEAH!"

"So, now, does anyone have any questions?" Ammy said defiantly.

"I do," Madjick spoke up.

"What!?" Everyone said in unison.

"Why should we want to fight Asgore about this? Why can't we just… you know, use diplomacy?"

"Oh Madjick, you silly! That's the plan! Weren't you listening?"

"Oh ok."

 _Writer's Note: One REALLY boring trek through Hotland later..._


	11. Plot Twist

Slam! Undyne kicked down the door. Asgore looked up, but the sight that greeted him was not the scheduled one. A squadron of monsters, all ready to fight, greeted his eyes. He staggered back, clearly shocked by this resistance. "What is the meaning of this?" he demanded.

"Asgore. You are a terrible creature, wishing to torture innocent children. Through the help of others, we all mustered the courage to confront you. Surrender peacefully, or we will be forced to fight you." Toriel said, fiercely. The monsters gathered around her all lowered into battle stances.

"Stop, please! I do not wish to fight any of you. I am truly sorry. But please, have mercy! I will repent for my sins."

"You deserve no mercy!" Undyne said, summoning a spear.

 **"Stop!"**

The determined shout rang through the halls. Everyone froze.

"This is **not** what I meant! We shall not harm him when he has shown no aggression." Ammy said, pacing forward. Noone dared to challenge her. She walked forward and stopped when she was face-to-face with Asgore.

"Thank you," he breathed.

"Don't thank me just yet."

"W-What?"

Suddenly, a red glow filled the room. When everyone opened their eyes, they were greeted by a terrible sight. Chara had appeared at last.

" **What? No warm welcome? I thought you, of all people, would be happy,** _ **Asriel.**_ **"**

 _Writer's Note: I recommend any good action scene music for next part. Just saying._

Flowey shivered. Ammy simply stood there, looking rather unimpressed. Chara struck, but Ammy simply put out a finger and blocked the blade. But then the knife fazed right through, striking her chest. She staggered back. While the other monsters cowered, Toriel summoned her fire. Asgore pulled out his trident. Sans and Gaster readied the Gaster Blasters, while Papyrus readied his bones. Undyne summoned some spears. Alphys pulled out her plasma gun. Mettaton(EX) struck a dramatic pose and pulled out his chainsaw. They all formed a protective circle around Ammy, while a healing monster tended to her. **"So, ready to fight, I see? Well, your efforts are in vain. You see, you may outnumber me, but I hold the cards. And determination is trump. Die!"** Chara said menacingly. The room went black.

Chara swung at Papyrus first. **32.** Sans looked outraged. He started to shake. Gaster reared, but then a flash of blue light filled the room. In his place stood a giant draconic skeleton. Gaster too started to do this. Another flash, this time purple, filled the room. In Gaster's place stood a slightly larger, albeit giant draconic skeleton. Papyrus looked as if he was going to do it, too, but Ammy intervened. "You're hurt."

"Huff.. you're right, I shouldn't."

Sans lunged, snapping at Chara with his giant maw. **35.** Chara recoiled, then took her knife down Sans's skull. Sans pulled his head back just in time. Gaster opened his mouth and fired. A beam of red light shot forth, hitting Chara square in the face. **999999.** But Chara didn't die. Toriel immediately shot flames at Chara, but she dodged. Asgore slashed with his trident. **23.** Undyne threw spears. They hit Chara straight in the elbow. **63**. Chara stopped in her tracks. Alphys then shot Chara in the other elbow. She dropped her knife. It hit the floor with a clang. Mettaton then lunged straight at Chara, brandishing the chainsaw like a warhammer. **67.** But then Chara bent down and picked up her knife in her mouth. She slashed, cutting right through Mettaton like a hot knife through butter. He collapsed. Alphys fired again, this time striking Chara in the ear. She scrambled over and picked up Mettaton. Sans took a step forward, shaking the entire room. He fired. Chara's body started to fade to dust. But it refused. Chara slashed. A crimson streak was left by the blade. It flew through the air, striking Toriel. **669**. Toriel kneeled. Asgore looked furious. He swung, and struck. **99999.** Suddenly, Flowey's tendrils whipped out of the ground and grabbed Chara. He shot friendliness pellets at her, again and again, but Chara only took one damage from each. Chara slashed his tendrils. She was free.

But then Frisk dashed forwards, the FIGHT button appearing in front of them. They struck. **420.** Chara struck. **20.** Frisk's soul started to break. But it refused. Gaster and Sans both fired. Chara dodged. Sans swung with one of his enormous clawed hands. They tore right down the middle. Gaster did the same, except he picked her up. He lifted her to his eye level, opened his mouth, and fired. He then dropped her down on the ground. Chara landed on her feet, then swung at Gaster's other hand. He roared in pain. She then swung at Sans's legs. Sans picked up his feet and flattened her. He lifted his hand up after what seemed like an eternity, but Chara was gone. But she reappeared right behind Frisk. Frisk tried to escape, but Chara took control.

Both Gaster and Sans reverted to their normal forms. They both looked exhausted. But Sans stepped forward. He said, "Welp. Guess it's time to change the plot, eh? Fighting me in a pacifist's body will be even harder, Chara."


	12. Well That Was Anticlimactic

The room went black once more. The battle interface appeared in front of Frisk. Flowey summoned the human souls and became Omega Flowey. Sans summoned Gaster Blasters and bones. Papyrus summoned just bones. Asgore brandished his trident once more, and Mettaton did the same with his chainsaw. Undyne, having suited up in her armor, summoned more spears. Alphys's claws crackled with electricity. And finally Ammy stepped forward, having pulled out the sword once again. She swung, but instead of the swirling magenta tornado, the same beam as the one the Gaster Blasters fired shot out. It hit Chara square in the face. "Deja vu," Sans commented, with a chuckle. His eye lit up blue, and all of the Gaster Blasters fired at once. The other monsters, this time, having learned from their mistakes, they all rushed at Chara as one mass. Everyone each struck her in a different location. Suddenly, red blades appeared. They rushed forward, striking each monster in turn. Ammy swung with her sword, striking Chara on the chest. Blood came rushing forth. Chara was shocked. **"H-How..?"** she stuttered, coughing up blood.

"Your time is over," Ammy replied. She raised her sword, grabbing the attention of everyone in the room. She struck downwards. But the blade just struck cold metal. Ammy looked up at the sound of the voice.

" **Ha ha ha ha ha ha ha ha ha ha hahahahahahahahahahahahahhahahahaha ha haha ha,** " Chara was on the other side of the room, bursting into maniacal laughter. "I **can't believe you** **actually fell for it! Haha! Gotcha, you fools!** " Chara started to transform, becoming more like Asriel. Everyone else stepped back, leaving Ammy to fight alone.

Chara was now about the size of Asriel. She wore a crown with huge goat horns in the shape of Asgore's. She also wore the same attire Asriel had, except she had the huge rainbow wings. Chara also had paws for feet and a huge serpentine tail. Her fingers were now clawed, but she wore tight purple leather gloves over her hands.

Ammy growled. Her left eye shone an even brighter yellow. The light made it impossible to look at for even a second. She sunk into a fighting stance, then lunged at Chara. Ammy was knocked back by Chara's tail. They repeated this multiple times, but after a while Ammy stopped. Her arms and legs were covered in gashes and one ear was bleeding. Yet she still stood tall. _**"How!? How are you still standing!? You should be dead! HOW!?"**_ Chara said.

"Heh.. heh.. You never realized, did you.. Heh. ehehehehehheehehehehehhehehehehehe.." Ammy echoed. "Eheheheheheh.. Now I'll show you my _true_ power.." Ammy said, beginning to pull out a giant shining paintbrush. Ammy crossed them and suddenly a huge power started emanating from her. A white light filled the room. When everyone opened the room, they were greeted by a new sight.

Ammy had become a truly fearsome warrior. Her blade reflected many colors, but the blade itself was a fluctuating double-edged blade with a shining rainbow aura. The pommel was made of a draconic pattern, with the magenta pearl set inside of a yellow diamond.

Ammy herself had also changed. She had shining yellow wings made of a single curving line that spread out into several other lines. In the center of those wings was a shining red sun. Her kimono was now patterned with cherry blossoms. Her hair had lengthened plentifully, and her wounds had healed. On her face was jagged purple lines, along with a purple crescent moon on her forehead. On top of her kimono, she wore armor that showed inspiration from many different universes. And lastly…

Her energy was bright and warm compared to Chara's ice-cold energy. .First, she teleported to Sans, who was slowly fading to dust. With one glowing hand, she touched him. He was healed instantly. "Thanks.." he breathed, "Now go fight Chara. You're the only one who can at this point." He let out a sorrowful chuckle before collapsing. "Don't worry, he's just asleep." Ammy said, "and I will, my friend, I will. Just for you.." she whispered. Then she teleported back to Chara. "I will fight, not to defeat you, but to protect those I care about. Not going anywhere for a while? Grab a snickers." Ammy said.

 _ **"W-What?"**_ Snap! Ammy dashed forward and broke Chara's right arm in one fluid motion. Chara roared in pain, before attempting to gore Ammy with her horns. But the horns hit empty space. Ammy had dodged the attack just in time, countering with a slash to the previously-damaged right arm. Chara stepped back, looking annoyed. Her face instinctively scrunched up in agony as she grabbed her useless arm and tore it right off. Black tendrils snaked down and reformed the arm. She clenched her fingers, as if she was testing the arm. _**"Hahahahahaha ahahahahahahaha hahah haha!" You can't defeat me if I can't be defeated!"**_

 __Suddenly, Sans stepped forward once more. "Actually, my experience with space-time would like a word with you," he said, his eye flaming cyan. A huge burst of flame erupted from it as he used his magic. He teleported, rushing forward. He kicked Chara straight in the face, knocking her back into one of the space-time rifts. She disappeared. "Welp, that sure was anticlimactic."

"Roll credits." Ammy said, reverting to her normal form."Well, at least that's over. But I think I'll stay here for a while. This is a really great place, actually. And since I caused you all so much trouble…"

"Ammy, that's ridiculous!" Papyrus said. Suddenly, he was interrupted by Toriel, who looked very happy. "You didn't cause us trouble…" she let off, letting Undyne finish. "You gave us all courage! Without you, we wouldn't have ever **dreamed** of confronting Asgore, and you wouldn't have ever defeated Chara!"

"Well, you're right. But, the least I can do is break the barrier." Ammy said. Everyone agreed with this.

Later…

The monsters stood at the exit to the underground, admiring the setting sun. "Sans, what's that giant ball?" Papyrus said.

"We call that the sun," Sans replied.

"Wowie! I can't believe I'm finally meeting the sun!" Papyrus said.

Ammy and Flowey stood in the background. "Well, Asriel, are you okay with this?"

"Well, at least I got souls.."

"You do know I'll jist stop you if you try anything stupid, right?"

"I know. But, maybe I can just do something else with them. But, you do know what this means, don't you?"

"Yeah. I know that Sans knows. He told Gaster about it, and Gaster went to me. I just told Gaster to tell him that he's free to do whatever he wants. It's his problem, so it's his decision."

"Oh. Well then, what do you want to do with this world?"

"I think I'm just gonna live in it. I've had enough fourth-wall breaking for a while."

"Sounds good to me."

"Well then, let's join the others."

 _Writer's Note: Whew! I'm glad that's over. This is NOT the ending chapter, Chapter 13 will be the Epilogue. I WILL be making a sequel, but it will be a seperate story. Next time, I'll make a prologue. I will also be creating a master post of this on my Tumblr. My username is_ _ispikedthedrinks_ _and the username listed here is also the link to my page. Special thanks to Eliza Violet and Red Diz for being such great people and being supportive through every word of this. I hope you enjoyed, and have a great day(or night)!_


	13. An End To It All(Epilogue)

Entry Number 22: It's been 6 months. The humans mostly accepted us. We found out that Mt. Ebott is in Newfoundland. Toriel started her school, and Asgore works there as the gardener. Everyone used the new landscape to our advantage. Now we have our own town: Lumeo. It means "light". Ammy named it, actually. She said it was fitting. I trust her on that one, because I get it too. Heh. We all have our own houses. Undyne and I share a house for obvious reasons. Mettaton got this fancy mansion, but it's a condo compared to the New Palace. Which, of course, is Asgore's. Flowey lives there, too. That's why the courtyard gate is always open, so people can visit. Frisk, Sans, Papyrus, Gaster, and Toriel all live together. Their house is actually the west wing of the Palace. Asgore lives in the center. Grillby's is still open. Sans used his magic to move the entire place up here. Among other things. Muffet actually found another cave, and it's perfect for her. Ammy got her own mansion in the woods. It's a traditional Japanese one, and she invites me over to dinner all the time. One day she told me that she was actually from the universe of the anime Inuyasha. That was so shocking, but I knew she wasn't lying. I'm glad everyone's happy, but I'm getting this weird feeling that not everything is alright. Oh, I bet it's just me.

Ammy walked down the sidewalk and up the driveway of Alphys and Undyne's house. She knocked on the door. Undyne answered. "Oh, hey Ammy. What's up?"

"Actually, I just wanted to talk to Alphys. Is she home?"

"Yeah. 2nd floor, first room on the left."

"Thanks."

Ammy walked in, opening the door slowly. "Hey, Al, you in here?"

"Oh! Ammy! I didn't think you would actually come. Here's the thing you asked for." She handed Ammy a strange device. Ammy handed her a 20$ bill.

"Thanks." Ammy said, leaving the room. She then walked out, said "Thanks" to Undyne, and walked home from there. As she stepped up the familiar cobblestone path, she thought about why she was doing this. Why she was going out of her way to SAVE someone who didn't want her to. Why she did what she did. Why she changed the fate of this universe forever. She stopped at the SAVE point. A textbox appeared. " **The welcoming sight of such a welcoming home fills you with DETERMINATION."** File saved.

 _Notes:+Ammy's house is nearly identical to the Nura clan mansion is Nura:Rise of the Yokai Clan(aka Nurarihyon no Mago)._

 _+Alphys and Undyne's house is a 3-floored modern house._

 _+The SAVE points in Lumeo are in the following locations: next to the centre fountain in the Royal Courtyard, along the cobblestone path to Ammy's house, and at the entrance to the town itself._

 _+The school is called Lumeo K-12. It's the home of the Ferrets. The mascot is Tarik the Ferret (a reference to Spirit Animals)_

 _+Muffet's cave is actually a disused quarry, but noone has told her that. Ammy and Sans went in to excavate it and came out with 17 broken pickaxes, 3 cranes, and the two halves of a giant drill._

 _+Mettaton now has three fountains with him on it. One has his rectangle form(left), One is Mettaton EX(centre), and the last one has Mettaton Neo(right)._

 _+Flowey has a ton of things. He also wanted a chess set, and on his request, Ammy moved the music box statue to the garden. It is now the centrepiece for the Centre Fountain,(heh, double center) and plays "Memory" throughout the entire town._

 _+Flowey also sometimes uses the souls to feel. When he needs to have a certain trait, he uses tthe according soul._

 _+The spark of a soul within Flowey mentioned in earlier chapters is a reference to Ask Frisk and Company. It wil be used as a plot point in the sequel._

 _+Sans's room features the same door as the old one, the classic troll treadmill, the self-sustaining tornado, the scandalous socks, and the same bed. The only new feature is a 40-inch flat-screen TV mounted onto the left wall._

 _+Gaster's room is filled with super-sciency things. He even has a periodic table shower curtain!(Note: I went to Bed Bath and Beyond one day and found an actual periodic table shower curtain. It was hilarious.)_

 _+Toriel's room is filled with food-themed furniture. She has a total of 4 kitchens._

 _+Frisk's room is filled with kid things. They play with toy soldiers and use dollhouses as the forts. And have knight action figures riding Barbie horses._

 _+Papyrus's room is the same as always. He now has a bathroom!_

 _+Alphys's room is filled with anime merchandise. Little does Ammy know, she bought plushies of Inuyasha, Sesshomaru, and Inutaisho._

 _+Undyne and Alphys share a room. Their living room has Undyne's piano. They had a fireplace, but it was remade by Gaster and Alphys to be a iceplace. It's filled with-ice cold flames. When you put your hands in it, your hands actually get wet._

 _+Sans and Ammy built a laboratory. In 2 weeks. All by themselves. But it took them a full month to install all of the technology. But Sans, Ammy, Alphys, and Gaster all decided on a name: Innovation 's surprisingly fitting, as this is where the four of them take innovative ideas from all over the world and make them into reality using a combonation of magic and technology. They made so much money off of this that they could afford to buy all of New York._ _ **Twice.**_ _But they put it in a vault for later._

 _+Ammy also started a stray-rescue organization. It was a huge success; now Burgerpants, Lesser Dog, Greater Dog, Doggo, Dogamy, and Dogaressa all work there._

 _+Bratty and Catty started a supermarket: Trash Mart. Despite the name, they've had a huge amount of satisfied customers._

 _+Muffet started a bakery. She has also had huge success._

 _+Mettaton is now a celebrity idol. His shows are popular across the entirity of Canada and the US._

 _+Some humans started moving in to Lumeo. Diana, Helen, Linda, and Frank immediately had a change of attitude as soon as PTA Sans came around._

 _+Nearly everyone else has two jobs. Actually, almost everyone works at Lumeo K-12. Undyne, of course, is the gym teacher. Gaster teaches Physics and the other advanced Science classes. Toriel teaches Monster History and Home-Ec. Alphys teaches Woodworking(Shop 1) and some of the more basic science classes. She also teaches robotics. Ammy serves as principal, but she also teaches Metalworking(Shop II). Asgore is the gardener, but also teaches Nature classes and Survival. Surprisingly, Flowey teaches Character classes and how to be a good person. Overall, the school has recieved an insane amount of good reviews._


End file.
